This invention is in the field of data acquisition and processing systems. More particularly, it is concerned with apparatus and methods for detecting analog signals at widely spaced locations, amplifying these signals and digitizing to 1 bit, and transmitting them as trains of single bit digital pulses over a single pair of conductors to a distant recording point, and compositing pluralities of said signals.
Still more particularly, it concerns a system in which a plurality of separate detectors produce analog signals which are amplified, digitized to 1 bit and transmitted by a two conductor cable to a disc recording means, and there composited with succeeding repetitions of the signals.
While this invention is useful in the acquisition of any type of analog signals such as in the field of data collection, vibration analysis, sonar signaling, nuclear technology, and so on, it is most appropriately useful in the area of seismic prospecting and as a matter of convenience, and not in any limiting way, it will be discussed in that application.
In the prior art systems the seismic signals detected by the geophones have normally been transmitted by separate pairs of conductors to the recording track. Here they are amplified in high gain, gain ranging amplifiers, multiplexed into sequential amplitude samples of successive traces, and digitized to 15 or more bits, after which they are temporarily recorded on a magnetic medium. The next repetition of the elastic wave signal is processed in a similar way and successive amplitude measurements of given traces at a given time are summed, and the sum is again recorded on the magnetic medium,